1 : 31680 The western boundary of this plan is formed by the Peddars Way, a Roman road laid down circa AD61. The ruins of Castle Acre are depicted along this road. Excavations here have uncovered a unique grain-processing plant, comprising a granary, a barn, a kilnhouse, a malthouse and a brewhouse. To the north-east of the castle are the ruins of a former priory belonging to the Cluniac Order, set on an incline above the River Nar. This small river, highlighted in blue on the plan, provided the priory with the greater part of its water supply via a 'monastic drain' - a general descriptive term for fenland drainage systems characterised by large overflow ditches. Metcalf, Edward B.